Sustainable Farming with Conservation Tillage: Techniques and Best Practices

In contemporary agriculture, meeting the increasing global food demand while safeguarding soil health is a pressing challenge. Conservation tillage, a forward-thinking technique, is gaining recognition for its ability to enhance soil fertility and boost carbon sequestration.

However, as the need to produce higher yields intensifies, it is crucial to adopt conservation tillage in a way that prevents soil degradation and positions the land as a reservoir of resources rather than a source of environmental pollutants.

Horta S.r.l. provides indispensable support in implementing conservation tillage practices effectively, ensuring that agricultural production can scale sustainably to meet growing food demands while preserving soil integrity and minimizing ecological impact.

Soil Tillage: What Are We Referring To?

When we talk about soil tillage, we are referring to the mechanical manipulation of the soil with the objective of cultivating crops. This practice significantly influences key soil characteristics, such as water retention, temperature, infiltration processes, and evapotranspiration.

Soil tillage is essential for agricultural production but has a direct impact on the soil and, consequently, on the environment.

However, increasing crop yields to meet the growing food demand must be achieved in a way that minimizes soil degradation and prepares the soil to act as a reservoir of resources rather than a source of atmospheric pollutants.

In this context, conservation tillage, supported by complementary practices such as soil cover and crop diversification, has emerged as an effective strategy to ensure sustainable food production while preserving environmental integrity.

This approach forms the foundation of Conservation Agriculture (CA), which is defined as a method of managing agro-ecosystems aimed at improving and maintaining productivity, increasing profitability, and ensuring food security, while simultaneously preserving and enhancing the natural resource base and the environment.

But How Do We Define Conservation Tillage?

But How Do We Define Conservation Tillage?

Conservation tillage is a soil management system that ensures at least 30% of the soil surface is covered by crop residues after planting, with the goal of reducing water-induced erosion.

This method is described as an approach to seedbed preparation that includes the use of residue mulch and increased soil surface roughness, which are considered essential criteria.

Conservation tillage represents an ecological approach to soil management and seedbed preparation. Transitioning from conventional tillage to conservation tillage, when performed in accordance with the principles of Conservation Agriculture, can lead to numerous benefits:

• Improvement of soil structure,
• Increase in soil organic carbon,
• Reduction in erosion risks,
• Conservation of soil water,
• Reduction in soil temperature fluctuations, and
• Overall enhancement of soil quality and its environmental regulatory capacity.

Generally, there are four main types of conservation tillage:

• No-tillage (NT): The soil is not disturbed by tillage throughout the year. Crop residues are left on the soil surface, reducing erosion and improving water retention. During planting, the soil may be disturbed in narrow strips, typically no more than one-third the width of the row, to allow seed placement. Other common terms for no-tillage include direct seeding, strip-till, and zero-till.
• Reduced Tillage (Minimum Tillage): This involves shallow soil tillage, generally between 10 and 15 cm deep, without completely overturning the soil clods and only partially burying the crop residues present in the field, using tools like chisel plows or disk harrows.
• Strip-tillage (Strip-till): This method involves tilling the soil in strips along the planting rows, leaving the space between the rows intact. This is also a shallow tillage practice, generally between 10 and 15 cm deep, affecting only 25-45% of the total surface area. This tillage practice is commonly performed simultaneously with planting and can be combined with subsoiling in the rows to break up compacted soil layers.
• Ridge-tillage (Ridge-till): Specialized planters and cultivators are used to form and maintain permanent ridges on which crops are grown. Crops are planted on top of the ridge after removing the residues, which are left between the rows. Cultivation is used to form and maintain the ridges and to manage weeds.

It's important to emphasize that conservation tillage can be combined with other practices to enhance the benefits provided by reduced tillage and increased soil surface cover.

Complementary practices include:

• Cover crops;

Here is an in-depth article on cover crops:

• Crop rotations that optimize biomass production;

Here is an in-depth article on crop rotation:

• Sowing practices that regulate plant population, such as alternating row spacing to manage residues;
• Integrated pest and nutrient management.

These types of practices collectively form the foundation of conservation tillage systems.

CONSERVATION TILLAGE SYSTEMS

How Do We Define a Conservation Tillage System?

A conservation tillage system is defined as a set of advanced and integrated management practices within an agricultural production system.

These practices, combined with other conservation measures, aim to improve environmental management, agricultural profitability, and long-term sustainability.

The best management practices in conservation tillage systems include:

• Minimizing soil disturbance
• Crop rotation
• Permanent soil cover
• Increasing surface residue
• Reducing the use of inputs
• Improving soil quality
• Traffic control

By reducing soil tillage and effectively managing crop residues, these systems not only enhance agricultural productivity but also contribute to the long-term health of the agricultural environment.

What Are the Advantages of Conservation Tillage?

Conservation tillage offers a range of benefits for soil, the environment, and agricultural production.

These benefits vary depending on the specific system used, but overall, reducing soil tillage helps improve various soil properties and reduce environmental impact.

Below, we analyze the benefits of conservation tillage, categorized by key soil properties and their impact on agriculture.

Impact of Tillage on Soil Physical Properties

The effects of conservation tillage on soil properties vary, and these variations depend on the particular system chosen.

Advantages of No-Tillage (NT):

• Reduction of Soil Disturbance: NT technologies are highly effective in reducing soil and crop residue disturbance, helping to moderate soil evaporation and minimize erosion losses (Lal, Reicosky, e Hanson, 2007).
• Increased Aggregate Stability: In no-tilled soils, more stable aggregates are observed in the upper soil surface compared to tilled soils, leading to greater overall porosity in NT soils.
• Improved Water Conservation: NT is particularly effective in conserving water in the humid and sub-humid regions of the tropics, protecting the soil from erosion and enhancing infiltration.
• Greater Water Retention Capacity: Under NT, the water retention capacity or moisture content in the topsoil layer (0–10 cm) is higher compared to plowed soils (McVay et al., 2006).

Advantages of Minimum Tillage (MT):

• Improved Aggregate Stability and Increased SOC and Nitrogen: Minimum tillage (MT) not only improves aggregate stability but also increases concentrations of soil organic carbon (SOC) and nitrogen (N) within the aggregates at soil depths between 5 and 8 cm.
• Improved Soil Pore System: Minimum tillage enhances the soil pore system by increasing microporosity. This leads to an increase in soil water content and, consequently, greater water availability for plants.

No-tillage (NT) offers significant advantages, such as reducing soil disturbance, better water conservation, and greater water retention. Similarly, minimum tillage (MT) improves aggregate stability and soil microporosity, making more water available to plants.

Impact of Tillage on Soil Chemical Properties

The chemical properties of soil that are typically influenced by tillage systems include pH, cation exchange capacity (CEC), exchangeable cations, and total soil nitrogen.

Effects of No-Till (NT):

• Soil pH: Tillage practices generally do not have a significant effect on soil pH (Rasmussen, 1999). However, it has been reported that soil pH is lower in no-till systems compared to conventional tillage (CT) systems (Rahman, Okubo, Sugiyama, & Mayland, 2008). The lower pH in Zero-Tillage (ZT) soils is attributed to the accumulation of organic matter in the top few centimeters of ZT soil, which causes an increase in electrolyte concentration and a reduction in pH (Rahman et al., 2008).
• Exchangeable Cations: Studies by Ismail et al. (1994) e Rahman et al. (2008) have highlighted that exchangeable cations such as Ca, Mg, and K were significantly higher in surface soil under NT compared to plowed soil.

Effects of Minimum Tillage (MT):

• Soil pH and SOC Content: It has been demonstrated that minimum tillage (MT) leads to significantly higher pH and SOC content compared to conventional tillage (CT). This suggests that reduced soil disturbance is beneficial for improving soil chemical quality.

Effects of Conventional Tillage (CT):

• Negative Effects on Exchangeable Cations and Nutrients: Conventional tillage (CT) soils recorded the lowest values of soil organic matter (OM), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg). This could be due to the inversion of surface soil during plowing, which brings less fertile subsoil to the surface and promotes nutrient leaching.

No-tillage (NT) offers important advantages, such as higher levels of essential soil nutrients (like calcium, magnesium, and potassium) and improvements in organic carbon content and the soil's ability to retain nutrients. However, it may lead to a slight reduction in soil pH over time, making the soil slightly more acidic.

Minimum tillage (MT) is beneficial for maintaining a more balanced pH and increasing organic carbon in the soil. This means that by disturbing the soil less, the chemical quality of the soil is improved, which is essential for plant growth.

In contrast, conventional tillage (CT), which involves more intensive plowing, can reduce soil fertility. This occurs because plowing can bring less fertile soil layers to the surface and cause the loss of valuable nutrients, making the soil less productive in the long term.

Impact of Tillage on Soil Biological Properties

The most biologically influenced soil property by tillage is the soil organic carbon (SOC) content. Organic matter in the soil plays a crucial role as it significantly impacts the activities of soil organisms, which, in turn, regulate and determine SOC dynamics.

Effects of No-Tillage (NT):

• Increase in Earthworm Population: In no-tilled soils, the earthworm population is significantly higher compared to tilled soils. This is important because earthworms help improve soil fertility, making it healthier and more productive.
• Better Resource Utilization by Microorganisms: In no-tilled soils, microorganisms utilize nutrients differently than in tilled soils, creating a microbial community that can be more conducive to soil health.

Effects of Reduced Tillage:

• Increase in Surface Earthworm Activity: With less intensive tillage, there is an increase in the activity of surface-dwelling earthworms. This improves soil quality, making it more fertile and nutrient-rich.

Effects of Intensive Tillage:

• Reduction in Beneficial Fungi and Increase in Bacteria: When soil is intensively tilled, beneficial fungi in the soil decrease, while bacteria increase. This occurs because tillage disrupts the fungi present in the soil, altering the natural balance of the microbial community.

No-tillage (NT) promotes a greater presence of earthworms, which significantly contribute to soil fertility, and creates a more favorable environment for microorganisms, optimizing nutrient utilization.

Reduced tillage, on the other hand, enhances surface earthworm activity, improving soil quality without causing excessive disturbance.

In contrast, intensive tillage can reduce the population of beneficial fungi and increase that of bacteria, disrupting the soil's natural balance and compromising its long-term fertility.

Impact of Tillage on Crop Yields

The impact of tillage on crop yields is related to its effects on root growth, water and nutrient use efficiency, and ultimately agronomic yield.

Effects of No-Tillage (NT):

• Increase in Root Mass: A 22% increase in root mass under NT compared to conventional tillage (CT) has been reported. This is due to the presence of cracks, channels created by earthworms, and a greater number of biopores, which facilitate root growth.
• Effects on Root Density: There is an increase in root density only in the surface layers of the soil under NT, as compaction in deeper layers can hinder proper root development (Martínez et al., 2008).

Effects of Minimum Tillage (MT):

• Higher Corn Root Mass: The root mass of corn was consistently higher under MT compared to other types of tillage. This happens because minimum tillage breaks up the compact soil surface typical of Zero Tillage (ZT) without causing the intense soil disturbance that occurs with conventional tillage (CT), thus allowing for better root growth.

Effects of Conventional Tillage (CT):

• Increased Root Penetration: Conventional tillage allows for greater root penetration, but due to the intense soil disturbance, it may subsequently limit root growth.

Effects of Zero Tillage (ZT):

• Reduced Root Development: In soils managed with Zero Tillage (ZT), root mass is significantly lower compared to tilled soils. This suggests that soil compaction under ZT hinders root development and the growth of the main root axes (Martínez et al., 2008).

No-tillage (NT) promotes greater root growth in the surface soil layers, thanks to the presence of biopores and earthworm channels.

Minimum tillage (MT) is advantageous for maintaining resilient soil and supporting healthy root growth, particularly in corn.

On the other hand, conventional tillage (CT) allows good root penetration, but intense soil disturbance can limit growth in the long term.

Finally, Zero Tillage (ZT) can cause soil compaction that hinders root development, limiting growth.

Impact of Tillage on the Atmosphere

The impact of soil tillage on the atmosphere primarily occurs through the emissions of greenhouse gases from soil to the atmosphere (Lal et al., 2007).

It has been reported that about one-third of global greenhouse gas emissions are attributed to changes in agriculture and land use, including deforestation in tropical areas, of which 74% comes from developing countries.

Effects of No-Tillage (NT):

• High Carbon Sequestration: One of the main advantages of no-till is its ability to sequester large amounts of carbon in the soil. The conversion from conventional tillage to no-till can lead to carbon sequestration ranging from 367 to 3667 kg of CO2 per hectare per year(Tebrügge & Epperlein, 2011).
• Reduction in Organic Matter Decomposition and CO2 Emissions: Conservation tillage practices like no-till reduce the exposure of undecomposed organic matter to microbial processes, thereby limiting the decomposition of soil organic matter (SOM) and decreasing CO2 emissions.
• Reduction in N2O Emissions: In no-till managed soils, nitrous oxide (N2O) emissions are significantly lower compared to tilled soils.

Effects of Conventional Tillage (CT):

• Increase in N2O Emissions: It has been shown that tilled soils release significantly higher amounts of N2O compared to no-till soils(Kessavalou et al., 1998).
• Greater Aeration and Potential for Gas Emissions: Increased aeration in tilled soils boosts oxygen availability, which can lead to a higher aerobic turnover and thus increased greenhouse gas emissions (Skiba, van Dijk, & Ball, 2002).

General Effects of Tillage on Greenhouse Gases:

• Influence on Other Greenhouse Gases (GHG): Besides carbon, other greenhouse gases like nitrous oxide (N2O) and methane (CH4) are influenced by soil tillage regimes. About 38% of N2O emissions into the atmosphere come from soils (Bellarby, Foereid, Hastings, & Smith, 2008), while methane is considered one of the most potent greenhouse gases after carbon dioxide.

No-tillage (NT) offers significant environmental benefits, such as increased carbon sequestration in the soil and reduced greenhouse gas emissions like CO2 and N2O.

In contrast, conventional tillage (CT) can increase greenhouse gas emissions, particularly nitrous oxide, due to greater soil aeration.

Overall, soil tillage has a significant impact on greenhouse gas emissions, influencing not only carbon but also other important gases like methane and nitrous oxide.

Importance of Careful Planning in Conservation Tillage: Challenges and Solutions

As with the implementation of cover crops and crop rotations, it is essential to carefully plan the adoption of conservation tillage practices.

Without proper guidance and a well-defined strategy, these practices can lead to several disadvantages that could compromise soil health and crop productivity.

Disadvantages of Poorly Planned Conservation Tillage:

1. Requires Specific Machinery: The equipment necessary for conservation tillage can be expensive and not always available to all farms.
2. Not Suitable for All Soil Types: Some soils may not respond well to these techniques, necessitating modifications or additional interventions.
3. Does Not Allow for Residue Burial: In some cases, the inability to bury crop residues can lead to management problems and phytotoxicity.
4. Requires Specific Knowledge: Conservation tillage involves a deep understanding of soil and crop dynamics, and incorrect application can significantly reduce the expected benefits.
5. Can Lead to Insufficient Weed Control: The lack of mechanical tillage can make weed control more difficult, increasing the need for herbicides.
6. May Cause Soil Cracking: In certain soil types, the absence of tillage can promote the formation of cracks, increasing susceptibility to erosion

The Role of Horta S.r.l. in Conservation Tillage

Horta S.r.l. supports farms in addressing these challenges through an analytical and data-driven approach, customizing conservation tillage practices to improve soil health and reduce the use of chemical inputs.

Horta S.r.l. provides assistance in selecting tillage techniques, managing risks, and adapting to local conditions, ensuring sustainable and productive agricultural practices in the long term.

If you want to know more about regenerative agriculture, we invite you to watch our video on YouTube!

References

• Lal, R., Reicosky, D.C., & Hanson, J.D. (2007). Evolution of the plow over 10,000 years and the rationale for no-till farming. Soil and Tillage Research, 93(2007), 1-12.
• Rahman, M.H., Okubo, A., Sugiyama, S., & Mayland, H.F. (2008). Physical, chemical and microbiological properties of an Andisol as related to land use and tillage practice. Soil and Tillage Research, 101(2008), 10-19.
• McVay, K.A., Budde, J.A., Fabrizzi, K., Mikha, M.M., Rice, C.W., Schlegel, A.J., et al. (2006). Management effects on soil physical properties in long-term tillage studies in Kansas. Soil Science Society of America Journal, 70(2006), 434-438.
• Busari, M. A., Kukal, S. S., Kaur, A., Bhatt, R., & Dulazi, A. A. (2015). Conservation tillage impacts on soil, crop and the environment. International Soil and Water Conservation Research, 3(2), 119-129. https://doi.org/10.1016/j.iswcr.2015.05.002
• Anikwe, M.A.N., & Ubochi, J.N. (2007). Short-term changes in soil properties under tillage systems and their effect on sweet potato (Ipomea batatas L.) growth and yield in an Ultisol in south-eastern Nigeria. Australian Journal of Soil Research, 45(2007), 351-358.
• Lal, R. (1997). Long-term tillage and maize monoculture effects on a tropical Alfisol in western Nigeria. II. Soil chemical properties. Soil and Tillage Research, 43(1997), 131-139.
• Rasmussen, K.J. (1999). Impact of ploughless soil tillage on yield and soil quality: A Scandinavian review. Soil and Tillage Research, 53(1999), 3-14.
• Doran, J.W. (1980). Soil microbial and biochemical changes associated with reduced tillage. Soil Science Society of America Journal, 44(1980), 765-771.
• Boone, F.R., & Veen, D.E. (1994). Mechanisms of crop responses to soil compaction. In B.D. Soane & C. Van Ouwerkerk (Eds.), Soil compaction in crop production (pp. 237-264). Elsevier.
• Davis, J.G. (1994). Managing plant nutrients for optimum water use efficiency and water conservation. Advances in Agronomy, 53(1994), 85-120.
• Martinez, E., Fuentes, J., Silva, P., Valle, S., & Acevedo, E. (2008). Soil physical properties and wheat root growth as affected by no-tillage and conventional tillage systems in a Mediterranean environment of Chile. Soil and Tillage Research, 99(2008), 232-244.
• Ismail, L., Blevins, R.L., & Frye, W.W. (1994). Long-term no-tillage effects on soil properties and continuous corn yields. Soil Science Society of America Journal, 58(1994), 193-198.
• Tebrügge, F., & Epperlein, J. (2011). ECAF position paper: The importance of conservation agriculture within the framework of the climate discussion. In ECAF, European Conservation Agriculture Federation (2011). Retrieved from https://www.ecaf.org/docs/ecaf/positionpaperco2ecaf.pdf. Accessed 18.12.14.
• Kessavalou, A., Mosier, A., Doran, J., Drijber, R., Lyon, D., & Heinemeyer, O. (1998). Fluxes of carbon dioxide, nitrous oxide, and methane in grass sod and winter wheat-fallow tillage management. Journal of Environmental Quality, 27(1998), 1094-1104.
• Skiba, U., van Dijk, S., & Ball, B.C. (2002). The influence of tillage on NO and N?O fluxes under spring and winter barley. Soil Use and Management, 18(2002), 340-345.
• Bellamy, J., Foereid, B., Hastings, A.F.S.J., & Smith, P. (2008). Cool Farming: Climate impacts of agriculture and mitigation potential. University of Aberdeen. Retrieved from aura.abdn.ac.uk.